Electrostatic spray drying of microorganisms

Abstract

The present disclosure relates to a process for electrostatic spray drying of a living microorganism, the process comprising the following steps: a. Providing a suspension, comprising a number of components, including a microorganism, a solvent and an additive; b. Applying an electrostatic charge to said suspension; c. Forming droplets of said suspension; d. Drying said droplets, thereby forming dried particles; and e. (Optionally) collecting the dried particles.

1 . A process for electrostatic spray drying of a living microorganism, the process comprising:
 applying an electrostatic charge to a suspension comprising a live microorganism, a solvent, and an additive, wherein the suspension comprises at least 35% by weightwater;   droplets of said suspension;   said droplets, thereby forming dried particles; and   optionally, collecting the dried particles.   
     
     
         2 . The process according to  claim 1 , wherein the electrostatic charge is applied by an electrode in contact with said suspension, wherein said electrode has an electric potential difference, with respect to ground, below about 40 kV. 
     
     
         3 . The process according to  claim 2 , wherein the electric potential difference, with respect to ground, of the electrode varies over time. 
     
     
         4 . The process according to  claim 1 , wherein the microorganism has a lower effective dielectric property than one or both of the additive and the solvent. 
     
     
         5 . The process according to  claim 1 , wherein themicroorganism comprises facultative anaerobic bacteria or strict anaerobic bacteria. 
     
     
         6 . The process according to  claim 1 , whereinforming droplets is carriedwith a two-fluid nozzle. 
     
     
         7 . The process according to  claim 1 , wherein forming droplets is carried out with an atomizing gasselected from one or more of an inert gas, a noble gas, and an alkane gas. 
     
     
         8 . The process according to  claim 1 , wherein the suspension comprisesas at least 40% by weight water. 
     
     
         9 . The process according to  claim 1 , wherein the additive comprises a drying protectant. 
     
     
         10 . The process according to  claim 9 , wherein the dried particle comprises the drying protectant in an amount from about 50% by weight to about 90% by weight. 
     
     
         11 . The process according to  claim 1 , wherein the dried particles have a size from about 10 micrometers to about 200 micrometers, measured as Dv50 values. 
     
     
         12 . The process according to  claim 1 , wherein the size distribution of the dried particles is substantially unimodal. 
     
     
         13 . The process according to  claim 1 , wherein the dried particles comprise a microorganism having a viability of at least 1.0 × 10E4 per gram, as determined by one or more of the most probable number (MPN), the number of colony forming units (CFU), and the number of viable cells as measured by flow cytometry. 
     
     
         14 . A dried particle comprising living microorganisms embedded in a mass of additive, wherein the microorganisms are not present at the surface of the particle. 
     
     
         15 . The particle according to  claim 14 , wherein the particle is not layered, and has a substantially continuous radial gradient of additive. 
     
     
         16 . The process according  claim 1 , wherein the solvent has a higher dielectric constant than the additive, and the additive has a higher dielectric constant than the microorganism. 
     
     
         17 . The process according to  claim 9 , wherein the additive comprises a drying protectant comprising one or more selected from cyclitols, monosaccharides, disaccharides, polysaccharides, magnesium stearate, peptides, proteins, sugar alcohols, hydrogenated starch hydrolysates, fatty acid esters, and alginates and salts thereof. 
     
     
         18 . The process according to  claim 9 , wherein the additive comprises a drying protectant comprising one or more selected from inositol, dextrose, lactose, sucrose, trehalose, inulin, maltodextrin, starch, magnesium stearate, mannitol, sorbitol, and sodium alginate.